I cook fish in a foil envelope often if I don't know what else to do, put 1-2 slices of lemon, or 1 tbsp of lemon juice, a splash of olive oil and some spice like capers or dill or something like that. My favourite bag has the lemon juice, olive oil, coriander and thai basil and chilli.

ETA: I fold two pieces of foil together with a lifted top if that makes sense. I just chuck everything in & seal it up, no rubbing or mixing together first. I cook it in a low oven for 8-10 minutes.

I serve it over basmati rice with steamed veges.